The present invention refers to a target arrangement with a reversible circular target plate.
EP-0 127 272 describes a magnetron source in which a target arrangement positioned symmetrically to the source axis is pressed by a clamping arrangement on the back against a cooling plate. With respect to the central axis the target arrangement comprises symmetrically slanted bars that can be arranged to form a rectangular frame. In a sectional plane that comprises the central axis, these bars have peripheral, longitudinal, molded recesses on the outside as well as the inside in which the outer clamping bars and inner clamping strips engage, thereby bracing and pressing the bars against the cooling plate.
The disadvantage of the aforementioned target arrangement is that the latter, if arranged as a frame, cannot be reversed for sputtering from the back after the opposite side has been sputtered off, or that the intended lateral molded recesses or clamping bars and clamping strips do not permit such reversal of individual target bars, and that independently thereof the bracing of eroded sputtering surfaces against the cooling plate would drastically reduce the target cooling that is achievable when the target is still new. This means that the sputter process parameters would have to be drastically changed after the target bars have been reversed and in particular the sputtering power would have to be reduced.
From DE-OS-30 09 836 it is known that the target material to be sputtered can be better utilized by reorienting the sputter-eroded target segments on a heat sink. Various target clamping arrangements and reworking of the target segments are required.